The Garmin Forerunner series is a selection of sport watches produced by Garmin. Most models use the Global Positioning System (GPS), and are targeted at road runners and triathletes. Forerunner series watches are designed to accurately measure distance, speed, heart rate (optional), time, altitude, and pace, all of which can be important to athletes in training.

In 2006, the improved 205 and 305 appeared. These models are smaller than the first generation and feature a more sensitive SiRFstarIII GPS receiver chip.

In late 2007, the Forerunner 50 was introduced. As opposed to GPS, this model paired with a foot pod to measure displacement. The Forerunner 50 also came packaged with a USB stick that allowed training data to be transferred wirelessly to one's pc.[3] This feature has since become a staple of Garmin's more full-featured sport watches.

The Forerunner 405 was introduced in 2008 and is significantly smaller than its predecessors, only slightly outsizing a typical wristwatch. The 405 also featured improved satellite discovery and connection.

In 2009, Garmin produced three new models: the Forerunner 60 (an evolution of the Forerunner 50), the Forerunner 405CX (405 chassis), and the Forerunner 310XT (an evolution of the 305 chassis).[4] New features included additional battery life and vibration alerts on the 310XT and advanced calorie consumption modeling on all watches. The 310XT was also the first watch of the Forerunner series to be waterproof, thus allowing its use for swimming and on all legs of a Triathlon, also thanks to an extended battery life. In 2010 a firmware update added vastly improved openwater swimming metrics.[5]

In 2010, the Forerunner 110, 210 and 410 were introduced. The releases included the addition of a touch-sensitive bezel on the 410, presumably, although heavily debated, allowing for easier scrolling and selection of functions. It was touted as providing "unmatched reliability in sweaty, rainy conditions."[6]

The Forerunner 610 was released in the spring of 2011. It features a touch sensitive screen as well as vibration alerts.[7]

In 2012 the Forerunner 910XT was introduced, which is a development of the 310XT. This version was originally supposed to be released in Q4 of 2011, but the November date had slipped and it was eventually released in Q1 of 2012. New features are the inclusion of the SiRFStar iv chipset, a barometric altimeter, and improved swimming metrics using an accelerometer in the watch. This allowed it to automatically count pool lengths and to recognize swimming styles.[8]

A further addition to the series was the Forerunner 10, a simple watch offering just GPS tracking of activity's and run metrics like distance, pace and calories burned.

At the end of 2013 the Forerunner 220 and 620 were introduced, with color screens, Bluetooth Low energy (BTLE; allowing connections to some smartphones), and, for the 620 only, a touchscreen, Wi-Fi (allowing automatic activity download) and enhanced "running dynamics" given by an updated Heart rate monitor. These watches also abandon syncing via the ANT+ protocol in favor of wired (USB) and Wi-Fi (620 only) data transfers. They are also fully waterproof, but do not include any kind of swimming mode.[9][10]

In 2014, the Forerunner 15 and 920XT were introduced. The 15 is a development of the 10, adding activity tracking, increased battery life, footpod and hearte rate monitor capability. The 920XT is the successor of the 910XT, featuring all the capabilities of it (except ANT+ scale and fitness equipment capability) and adding features found in the 620 such as a color screen, Wi-Fi data transfers and running dynamics. Additionally, battery life over the 910XT was improved, daily activity tracking, GLONASS support and a swim drill mode added, and the 920XT is the first Garmin watch extensible with custom apps built using the Garmin Connect IQ software development kit.[11][12]

Announced in May 2015, the Forerunner 225 is the first Garmin watch with an integrated optical heart rate monitor.[13][14]

The Forerunner can be used to record historical data by completing a work out and then uploading the data to a computer to create a log of previous exercise activities for analysis.

Additionally, the Forerunner can be used to navigate during a workout. Users can "mark" their current location and then edit this entry's name and coordinates, which enables navigation to those new coordinates. The watch uses the hh.mm.mmmm (hours, minutes, and minute decimals) coordinate format. The 310XT can display additional formats; it also has a screen to display current coordinates in real-time.

The user can download a previously-traveled course/route to the Forerunner using Garmin's Communicator software together with the ANT+ technology, and then follow this course/route to "race" against this historical course/route. Until recently this download was possible via the tethered USB connection on the older 205 & 305 models. However, the current version of the software has eliminated this option, requiring the user to acquire a newer model with wireless connection in order to use this feature.

The user can also make new courses or routes, which can be downloaded to the watch and then followed. This is a convenient way to go on a cross-country bike ride while navigating with the Forerunner. Note: navigating with a course is better than navigating with a route, because a Garmin course can store more points than a Garmin route.

Additionally, a user can create downloadable points of interest (POIs) by creating a custom map with Google Maps. POIs can be transferred to the 205 or 305 but not to the 405 or 310XT.